The invention relates to a method for controlling the passage of printed media, especially of letters or envelopes, in a separating apparatus of a mail processing system. In that case, the letters can have different thicknesses and permissible formats in an irregular sequence. The processing of printed media occurring in that way is referred to as mixed mail operation.
Mail processing systems normally include:
a separating apparatus, in which the printed media are placed successively in stacks, separated and closed as required,
a franking and/or addressing machine with an optional integrated or preceding scale or balance, and
a depositing apparatus.
Reference is made in that regard to German Utility Model DE-M 96 09 167.3 in the Registered Design Bulletin of the German Patent Office dated May 24, 1997, Part Ia, Goods Class 18/02.
In mail processing systems of that type, it is difficult to achieve the greatest possible throughput per unit time. As a rule, an upper limit for the letter or envelope throughout is determined by a transport and printing speed of the franking machine. Consequently, it is worth attempting to match the throughput in the preceding devices to that upper limit.
A method of operating a high-speed mail processing machine for processing mixed mail of different thicknesses and different dimensions is known from European Patent EP 0 503 502 B1. The method includes the steps of conveying each postal item to a weighing station, weighing it and then printing a postage stamp. Those steps are activated and controlled by a drive control system corresponding to a number of sensors. The sensors are distributed around the machine, some of them being optical sensors. In addition, in that method, a specific sensor processor is caused to make access to the sensors and inform the drive control system about their state, after the drive control system has previously been activated. The access step includes the periodic execution of a main cycle in order, in that way, to make access to each sensor of a first group during each cycle, and to make access to each sensor in a second group only during some cycles but not all cycles. The sensor data are written into a RAM, to which the control system can make access.
Furthermore, a configuration for pre-separating printed media is known from German Published, Non-Prosecuted Patent Application DE 196 05 017 A1, in which the letters or envelopes, standing on one edge, are deposited one after another as a letter or envelope stack, and the letters are fed laterally away from the letter or envelope stack to a separating apparatus. In that case, the letters or envelopes are disposed between a spring-mounted pressure clip and at least one drive roll and a guide plate which is inclined slightly rearward. The standing surface for the letters or envelopes and the guide plate are orthogonal to each other.
Finally, a further apparatus for separating printed media, especially letters or envelopes, has been found, corresponding to German Published, Non-Prosecuted Patent Application DE 198 36 235 A1, corresponding to U.S. application Ser. No. 09/368,645, filed Aug. 5, 1999. That apparatus will be explained in more detail below with regard to FIG. 1.
It is accordingly an object of the invention to provide a method and a configuration for controlling the passage of printed media, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and devices of this general type, which match a throughput of letters or envelopes in a separating apparatus of the above-described type to a throughput of following devices, especially a following franking machine, and which improve service properties.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for controlling the passage of printed media, especially letters or envelopes, in a mail processing system, which comprises transporting printed media laterally away from a stack; providing a separating apparatus with different successive functional areas and a transition area between the functional areas; transporting the printed media more quickly in the functional area preceding the respective transition area, than in the respective transition area, until a printed medium has reached the transition area; transferring the printed media at a transfer speed to a following device having a transport speed; and adapting the transfer speed leading to the respective following device to the transport speed of the following device.
The invention is based on the concept that, in the franking machine, there must be a minimum distance from the leading edge to the leading edge of letters or envelopes which follow one another. This distance corresponds to the longest franking impression plus the width of the printing head plus a safety margin. Therefore, at least initially, the distance in the case of small short letters or envelopes is predefined. In the case of larger or longer letters or envelopes, the distance from leading edge to leading edge is necessarily greater than this minimum distance. In this case, the point is to keep the distance between the long letter or envelope and the following letter or envelope as small as possible and/or to achieve the greatest possible throughput.
Through the use of the invention, this problem is solved by controlling the transport speed in the individual passage areas of the letters or envelopes in the separating apparatus. Depending on the transport speed of the following device, the transfer speed is adapted to the latter. Therefore, the formation of a build-up in the following device is prevented from this side.
In accordance with another mode of the invention, the transport speed in the separating area is set to be higher than the transfer speed, until a letter or envelope has passed into the ejection area. This corresponds to accelerated transport in the separating area. This serves to increase the throughput in general and to reduce the distance between successive letters or envelopes in particular.
The transport speed in the separating area is set to be lower than or equal to the transfer speed, as long as there is a letter or envelope in the ejection area. This corresponds to normal transport in the separating area. This prevents the formation of a build-up upstream of the ejection area.
The transport speed in the pre-separating area is set to be higher than the transfer speed and higher than the increased transport speed in the separating area, as long as there is no letter or envelope in the input area of the separating area. This corresponds to accelerated transport in the pre-separating area. This likewise serves to increase the throughput in general and to reduce the distance between successive letters or envelopes in particular.
The transport speed in the pre-separating area is set to be lower than or equal to the normal transport speed in the separating area if a letter or envelope has reached the input area of the separating area and there is no further letter or envelope upstream of the ejection area. This corresponds to normal transport in the pre-separating area. This avoids the formation of a build-up in the input area of the separating area.
The transport speed in the pre-separating area is set to zero as long as there is a letter or envelope in the input area and in the other areas of the separating area. This corresponds to stopped operation or idling operation in the pre-separating area. This prevents the formation of a build-up or multiple extraction.
In accordance with a further mode of the invention, the transfer speed to the following device, that is the transport speed which is produced by the ejection roll pair, is continuously monitored. It is always lower than or equal to the transport speed set in the following device but kept somewhat higher, approximately 10%, than the transport speed in the initial area of the separating area, that is the transport speed produced by the separating elements. In addition, the transport speed in the pre-separating area, which is produced by the drive rolls with accelerated transport, is set to be correspondingly higher, approximately 30%, than the transfer speed in the separating area.
In accordance with an added mode of the invention, the letter or envelope is scanned in the input area of the separating area and immediately after being separated, in order to derive appropriate control signals for the drive in the pre-separating area and in the separating area, in combination with further scanning results.
In accordance with an additional mode of the invention, the letter or envelope is scanned in the ejection area of the separating apparatus in order to derive appropriate control signals therefrom for the pre-separating area, the separating area and the following device.
With the objects of the invention in view, there is also provided, in a mail processing system including a separating apparatus having a pre-separating area, a separating area and an ejection area, and a following device downstream of the separating apparatus, a configuration for controlling the passage of printed media in the mail processing system, the configuration comprising a drive disposed in the pre-separating area; a drive disposed in the separating area; a first encoder sensor for measuring a transfer speed of the printed media to the following device; a second sensor disposed in the ejection area for scanning printed media; a third sensor disposed in an input area of the separating area for detecting printed media; a fourth sensor disposed downstream of a separation in the separating area for detecting printed media; and an evaluation circuit connected to the first, second, third and fourth sensors, the evaluation circuit connected to the drives of the pre-separating and separating areas and bidirectionally connected to the following device, for outputting control signals.
In accordance with another feature of the invention, there is provided an ejector in the ejection area having an ejection roll pair including a stationary driven ejection roll and a spring-adjustable, indirectly driven ejection roll; the indirectly driven ejection roll connected synchronously to the first sensor; the first sensor supplying an output signal; and the evaluation circuit comparing the output signal supplied by the first sensor with a value corresponding to a transport speed in the following device, to provide a result supplied as a control signal to the drives in the pre-separating area and the separating area.
In accordance with a further feature of the invention, the ejection rolls define a line of contact therebetween, and the second sensor is disposed upstream or downstream of the line of contact.
In accordance with an added feature of the invention, the second, third and fourth sensors are reflection sensors.
In accordance with an additional feature of the invention, the second, third and fourth sensors for detecting printed media supply output signals; and the evaluation circuit combines the output signals from the second, third and fourth sensors for setting the drive in the pre-separating area to accelerated transport if the third sensor does not detect a printed medium; setting the drive in the pre-separating area to normal transport if the third sensor detects a printed medium and the fourth sensor does not detect a printed medium; setting the drive in the pre-separating area to idle if the third sensor and the fourth sensor detect a printed medium; setting the drive in the separating area to accelerated transport if the second sensor does not detect a printed medium; and setting the drive in the separating area to normal transport if the fourth sensor detects a printed medium.
In accordance with a concomitant feature of the invention, the output signal from the second sensor is also used for communication with the following device.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and a configuration for controlling the passage of printed media, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.